THE PASTERNS. 



249 



io obviate concussion. They have their origin from the head of the shank- 

 bone, and also from the heads of the splint-bones ; then descending Jown 

 the leg, they fill the groove between the splint-bones, but are not attached 

 to either of them ; a little lower down, they expand on ehher side, and, 

 approaching the pasterns, they divide, and are inserted into two little bones 

 found at the back of the upper pastern, one on each side, called the sessa 

 moid bones. (See p. 63, and in this cut, which represents the pastern and 

 foot, sawed through the middle.) They form a kind of joint, both with the 

 lower head of the shank-bone and the upper pastern-bone, to both of 

 which they are united by ligaments (^ and g), but much more closely tied 

 to the pastern than to the shank. The flexor tendons pass down between 

 them through a large mucous bag, to relieve them from the friction to 

 which, in so confined a situation, they would be exposed. This ligament 

 is continued over the sessamoids, and afterwards obliquely forward over 

 the pastern to unite with the long extensor tendon, and downward to the 

 perforated tendon, which it surrounds and fixes in its place, and also to 

 the smaller pastern-bone. A careful examination of the subjoined cut will 

 afford a familiar idea of this complicated structure. 



OUT OF THE PASTERN AND OTHER BONES, LIGAMENTS, ETC. 



a Sliank-bone. 



b Upper and larger past«rn-bone. 



c Sessainoid-bone. 



d Lower or smaller pastern-bone 



e Navicular or shultle-bone. 



y Coffin-bone, or bone of the foot. 



g Suspensory ligament inserted into the sessamoid-bone. 



A Continuation of the suspensory ligament inserted into the smaller pastern-bone. 



♦ Small inelastic ligament, tying down the sessamoid-bone to the larger pastera-booa. 



k A long ligament, reaching from the pastern-bone to the knee. 



I Extensor tendon inserted into both the pasterns and the coffin-bone. 



R 



